Previous research suggests that early temperamental biases shape the manner in which individuals perceive and process emotional information. These processes in turn create the conditions around which individuals view their own self-efficacy as well as the responses of others and hence contribute to the formation of adult personality. The interplay of early temperament and styles of cognitive processing is critical if researchers are to examine the complex trajectories of the development of social behavior into adolescence. With these considerations in mind, the current proposal will initiate an assessment in adolescence of a longitudinal sample that has been followed since early infancy. 150 infants were selected at 4-months of age from a larger normative sample based upon their motor and affective reactions to novel auditory and visual stimuli. These children were re-assessed at 9, 14, and 24 months of age and at 4 and 7 years of age. Previous assessments of this sample included measures of physiology, behavior, and maternal perception of temperament. The currently proposed study will provide assessments of these same subjects in adolescence when they are 14-16 years of age. 6 broad areas are to be assessed: Cognitive processing of emotional and social stimuli; resting physiological activity and reactivity to threat, self-concept and behavioral adaptation, observed social behavior in response to an unfamiliar peer, the presence of anxiety disorders, and the social contextual demands of adolescence. With data from these tasks, we will examine the confluence of early temperament and the demands of the social context in adolescence on styles of cognitive processing of social and emotional stimuli, the influence of early temperament on physiological reactivity to threat, and the mediating role of styles of cognitive processing and physiological reactivity on social and anxious behaviors.